Manufacture of phenolates



Patented June 2, 1931 UNITED STATES, j PAT ALBERT HmurnnonEIPzIe-oETzscmGEmvrANY MANUFACTURE or rnmronA'rns p No Drawing.Application filed July 7, 1930, Serial No. 166,034, andin Germany April9, 1929. i

This invention relates to the manufacture of alkali phenates accordingto which aromatic sulfonates are fused with caustic soda and theresulting mixture of sodium'sulphite and sodium phenate is separated byphysical means to obtain a phenate product which is remarkably free ofsodium sulphite and other impurities, and which may be employed directlyin subsequent syntheses.

Large quantities of phenol are employed in organic syntheses in the formof sodium salt, namely sodium phenate. 'For this purpose it has beencustomary heretofore to prepare the sodium phenate from the free 5phenol. However, since phenol is ,manufact-ured synthetically byflfusinga benzene sulfonate with caustic soda whereby sodium phenate is formed,from which free phenol is thereafter liberated by means of an acid,

' it is apparent that the prior practice is repetitious and wasteful.Nevertheless, this procedure has been considered essentlal to theproduction of a satisfactory product.

I have now discovered that one may ob T tain practically pure sodiumphenate directly from a fusion mass by permitting the 7 charge tostratify whereby sodium phenate forms a distinct upper layer and thesodium sulphite, which carries with it impurities such as sodiumsulphate, forms a distinct employ a slight excess of; caustic in thefusion, the excess caustic may, advanta--.

geously, be neutralized first, by the addition sodium phenate with thecharge, such as may be obtained from a previous batch.

grade technical sodium phenate directly and while obviatingthecustomarysteps of liberating the phenol and subsequently reformingthe phenate.

sodium phenate directly from the corre- I sponding aromatic sulfonatewhereby a pro duct is obtained which is free from sodium excess causticsoda. 1s permitted to settle :orstratify, sodium' two layers areisolated of phenol to the charge. I have further ob- The object of thisinvention, therefore, is

to afford a method of manufacturing high dium' benzene "sulfonatesulphite, excess caustic, sodium sulphate, tars, etc., and' whichm ayrbeused successfully in subsequent organic syntheses that re- -quire phenolin the form of its sodium-salt.

In general forthe purpose of this present invention, thej fusion of thearomatic sulfonates, such for example, as benzene sulfonate, with thecaustic soda may followthe present day practice. After the fusion iscomplete, the mixture will be found to con- -s1st essentially of sodium;sulphite, sodium tainingthe charge in I a molten 1 condition,

sufiicient phenol is added to'react with the Thereafter, thechargephenate being of"relatively lower specific from the sodium sulphitewhich forms thelower layer. Followingjthe' separation, the from eachother as by decantation, or in any other suitable 'manner.An:intermediate layer, which consists of a mixture of sodiums'ulphiteand sodium phenate, may be separated in a subsequent cycle of operation.The sodium phenate so lower layer. Inasmuch as it is desirable toobtained will: be found of sodium sulphite,- dium sulphate] andmay beemployed theses where a technical grade of sodium sulphite is required,as for example, in the ..manufactu'reof salicylic 'acidn A specificexample of an application of the-principles of my invention followscharge consisting hours, depending uponthewtech-ni'c s of fusion,employed. The charge: is fagitated during the fusion whichmayadvantageously be performed at of 235 partsof so-"Y being the subatmospheric I gravity forms an upper layer that is *distinct separatethe. stratified:

pressure and in the absence of an oxidizing atmosphere. After the fusionis complete, it will be found to contain seventeen to eighteen parts offree caustic soda, which is reacted by adding 41.542 parts of phenol.Thereafter the operation of the agitating mechanism is; interrupted and;the-fluid mixture permitted to settle into two layers, the upper layerconsisting of approximatelylfifi. parts of sodium phenate and thelowerlayer consisting of approximately 127*parts of sodium sulphite andvariousv impurities In order to hasten the settling operation and toobtain a, sharper separatioirone may advantageously admix a small amountof sodium phenate such as: hasbeen obtained from: the previous changerllfrthel line of demamcation between, the two layers is. not sharp;oraccurate .iiorany reason, one may change into, three parts; one partconsistingi of the uppenphenatelayen, another part consisting ofthelozweir sodiumysulphite; layer and the third part consisting: of an:intenmediate-= layer which may be; reworked in a: subsequent cycle, Thephenate product will be; found to. be; welzlzsuited' for the manufactureof salicyl c acid.

The present; application pertains; spethe feature which involves thesepllr i bni of; a. techni'cailagraide ofl'sodium phenate without.liberating. and: reforming the. sodium salt asihas: been; customaryheretofore; The; feature; described hereiuabove WhiQh: involyeseffecting the fusiiona under reduced pressures and advantageously in thepresence of an inert gaseous medium is claimed} in; copend-iimgapplication; Serial Number66,933filedyofieveri date It is to v be,noted; that: While the principles ofi-the invention? set forthheroine-bowie are. described in connection; with. the. manufacture ofphenol, (:C' HeQH), the principles are equally. applicable toithemanufacture of other phenols; made from}. corresponding aromaticsulfonaites, andiinclude hydroxybenzoic: acids, neslorcinoh;naphthols,alizarin, cnesotinic acid; hydroxynaphthoic acids: and similarcompounds, and? further: that. one

substitute potassium hydroxide ormixures 1 potassiumlhydroxidei andsodium hydroxide for: the; caustic soda. (sodium hydroxide): specifiedhereinabove. Obviously, the: inventiona is, not limited; to the:specific disclosures, but contemplates broadly the manufacture anddirectisolation: of a technical; grade of" alkali metal. phenates thefusion of cornesponding sulfonates with an alkali; wh re n m the:phenate isv obtained by stratifiofitiOIl, and; physical: separation.

What Lclaimi w Themethcd which; comprises fusing an L auyl: suliionatewith an alkali" whereby thereiscobtained: mixture containing an alkalimetal phenate corresponding to thearyl sulfonate, alkali sulfite andunreacted alkali, neutralizing the unreacted alkali by the addition of aphenol corresponding to the alkali metal phenate and subsequentlyallowing the phenate to stratify into a distinctseparable layer andfinally isolating the Stratified phenate.

2. The-method of" manufacturingsodium phenate which consists in fusingsodium benzene sulphonate with caustic soda, permitting the fusedmixture to form into physically, separable layers and finally isolatingthe sodium phenate layer.

3. Theamethod. of manufacturing sodium phenate which consists in fusingsodium benzene: sulphonate with, caustic soda, adding phenol to thefused; mixture in an amount vsuflicient to neutralize the; unreactedalkali, permitting the mixture to, form into physically separable layersof sodium; phe

nate and sodium sulfite. and finally; isolating the sodium; vphenate;layer.

4. The method which consists in, fusing an aryl, sulfonate with analkali; whereby a mixture of alkali metal sulfite, unreacted:

alkali and an; alkali metal phenate corresponding; to. the. arylsulfona-tia, is obtained, neutralizing the: unreacted alkaligby means ofa phenol cormspondingto the phenate,

Lafiix signature v ALBERT HEMPEL. V

